JP2014070265A - Barrel plating apparatus, and method for producing electronic component using the barrel plating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the improvement of plating efficiency.SOLUTION: The barrel plating device comprises: a bottom plate of a regular-n-sided polygon; n-pieces of side walls respectively contacted with the n-pieces of side of the regular-n-sided polygon forming the outer shape of the bottom plate; a vessel as the outer shape of a regular-n-sided polygonal prism not passing a liquid from the bottom plate and the side walls; rotating means of rotating the vessel by a rotary shaft passing through the center of the bottom plate, vertical to the bottom plate and tilted to below 90 degrees from the vertical direction; n pieces of side wall cathodes respectively mutually electrically independent to the inside of the vessel of the n-pieces of side walls; switching means of switching the conduction to the n-pieces of side wall cathodes; and an anode infiltrated into the space at the inside of the vessel.

Description

  The present invention relates to a barrel plating apparatus that performs plating on terminals and the like of electronic components, and a method for manufacturing an electronic component in which terminals and the like are plated using such a barrel plating apparatus.

Generally, solder plating or Sn plating is applied to terminals of electronic components, and in the case of chip-type electronic components, a technique for forming a plating layer by a barrel plating method is known. The barrel plating method uses a polygonal column container in which a side wall called a barrel is formed of a mesh or a plurality of through holes are provided in the side wall. Steel balls, which are conductive spheres as electronic components and media, are placed inside the barrel, and the barrel is immersed in a plating solution. The cathode is placed in contact with the electronic components or steel balls in the barrel, and the anode is placed in the plating solution outside the barrel, and energized while rotating the barrel, passing through the steel balls from the cathode to the terminals of the electronic components. The negative charge moves, and a positive charge such as Sn ²⁺ in the plating solution is attracted to the negative charge, thereby forming a plating layer on the terminal of the electronic component.

  In such a barrel plating method, there is also known a method of uniformly forming a plating layer by tilting the rotation axis of the barrel from the horizontal and stirring the electronic components in the barrel more efficiently. Is called an inclined barrel plating apparatus (see Patent Document 1).

JP 2006-274353 A

  The steel ball is used to electrically connect the cathode in the plating solution and the terminals of the electronic component, but in order to connect more terminals of the electronic component with the cathode, in other words, the terminals of the electronic component. In order to increase the chances of conducting with the cathode, it is better to have many steel balls. However, since the surface of the steel ball is also plated, if the number of steel balls is large, the ratio of the plating layer formed on the steel ball rather than the terminal of the electronic component is increased, and the plating efficiency is lowered.

  The present invention solves the above-described conventional problems, and an object thereof is to obtain an improvement in plating efficiency.

  In order to achieve the above object, the present invention has the following means.

  The invention according to claim 1 is constituted by a regular n-gonal bottom plate, n side walls in contact with each of the n sides of the regular n-square shape forming the outer shape of the bottom plate, the bottom plate and the side walls. A container that does not allow liquid to pass through the bottom plate and the side wall, and the container is rotated by a rotation axis that passes through the center of the bottom plate and that is perpendicular to the bottom plate and tilted to less than 90 degrees from the vertical direction. Rotating means, n sidewall cathodes electrically independent from each other inside the container of the n sidewalls, switching means for switching conduction to the n sidewall cathodes, A barrel plating apparatus including an anode that enters a space.

  According to the first aspect of the present invention, since the total area of the cathode can be increased due to the presence of the side wall electrode while reducing the formation of the plating layer on the side wall cathode, the steel ball can be reduced, and the plating efficiency can be reduced. It has the effect that it can improve.

  In the invention according to claim 2, in particular, the inner surface of the container of the bottom plate has n regions divided by imaginary lines drawn from the center of the bottom plate to each point of the outer shape of the bottom plate. And n bottom plate cathodes that are electrically independent from each other in each of the n regions of the bottom plate, wherein the bottom plate cathode is in contact with the side of the region of the bottom plate where the bottom plate cathode is located. It is a barrel plating apparatus electrically connected with the said side wall cathode provided in.

  Since the invention according to claim 2 further includes a bottom plate cathode, the total area of the cathode can be further increased, further steel balls can be reduced, and the plating efficiency can be further improved. Has a working effect.

  According to a third aspect of the present invention, in the barrel plating apparatus according to the first aspect, the step of putting an electronic component into the container containing the plating solution, the container is rotated by the rotating means, and the positive electrode is connected to the anode. Applying a potential, applying a negative potential to the least exposed sidewall cathode among the n sidewall cathodes by the switching means, stopping the container by the rotating means, and removing the container from the container And a step of taking out the electronic component.

  The invention according to claim 3 also has the same effect as that of the invention according to claim 1.

  According to a fourth aspect of the present invention, in the barrel plating apparatus according to the second aspect, the plating solution and the electronic component are charged into the container, the container is rotated by the rotating means, and a positive potential is applied to the anode. Applying a negative potential to the sidewall cathode that is least exposed among the n sidewall cathodes and the bottom cathode that is electrically connected to the sidewall cathode by the switching means; and And a step of stopping the container by rotating means and taking out the electronic component from the container.

  The invention according to claim 4 has the same effect as that of the invention according to claim 2.

  The barrel plating apparatus and the electronic component manufacturing method using the barrel plating apparatus of the present invention have an excellent effect that the plating efficiency can be improved.

Sectional drawing of the barrel plating apparatus in one embodiment of this invention The expanded view of the container of the barrel plating apparatus in one embodiment of this invention The top view of the baseplate inside the container of the barrel plating apparatus in one embodiment of this invention AA sectional view of FIG.

  Hereinafter, the present invention will be described in detail using an embodiment.

  1 is a sectional view of a barrel plating apparatus according to an embodiment of the present invention, FIG. 2 is a development view of a container of the barrel plating apparatus, FIG. 3 is a plan view of a bottom plate inside the container of the barrel plating apparatus, and FIG. FIG. 2 is an AA sectional view of FIG. 1.

  The container 1 is composed of a bottom plate 2 and side walls 3. The bottom plate 2 has a regular n-polygon shape, and is a regular octagon in the present embodiment. The side wall 3 is in contact with each of the eight sides of the regular octagon forming the bottom plate 2, and there are eight side walls 3a, 3b, 3c, 3d, 3e, 3f, 3g and 3h. In this embodiment, when expressed as the side wall 3, it is used as a general term for the eight side walls of the side wall 3a to the side wall 3h. The side wall 3 is not provided with a mesh and liquid cannot pass therethrough. The bottom plate 2 is also configured so that liquid cannot pass through it. With the above configuration, the outer shape of the container 1 is a regular octagonal column, and the liquid can be held in the space.

  The anode 4 is an electrode for supplying a positive charge and enters the space of the container 1. The suction nozzle 5 sucks the plating solution 10 from the container 1, and the supply nozzle 6 supplies the plating solution 10 to the container 1. The plating solution 10 is circulated by the suction nozzle 5 and the supply nozzle 6, and the concentration of metal ions can be kept within a certain range. The tips of the anode 4 and the suction nozzle 5 need to be immersed in the plating solution 10, but the supply nozzle 6 is not necessary. The anode 4 needs to be arranged so as not to contact the electronic component 11 and the steel ball 12.

  The rotation shaft 7 is an axis that passes through the center of the regular octagon of the bottom plate 2 and is perpendicular to the bottom plate 2, and the container 1 rotates around the rotation shaft 7. The rotating shaft 7 is inclined not with respect to the vertical direction but with respect to the vertical direction. In order to uniformly stir the electronic component 11 and the steel ball 12 in the container 1 to make the formation of the plating layer uniform, it is better to incline the rotating shaft 7 in this way. If the inclination angle is increased, the plating solution 10 will be spilled, so that it is less than 90 ° at the maximum. In this embodiment, the angle is 45 °. The shaft 8 has a cylindrical shape and supports the container 1, and the axis of the shaft 8 is configured to coincide with the rotation axis 7. The base 9 holds the shaft 8 in a rotatable manner, and a motor (not shown) as a rotating means for rotating the shaft 8 is built in the base 9. The shaft 8 is rotated by the driving force of the motor in the base 9, and the container 1 is rotated with the rotation of the shaft 8.

The plating solution 10 is a solution containing Sn ²⁺ ions to be a plating layer. The electronic component 11 has a terminal (not shown), and a plating layer is formed on the surface of the terminal by a plating method. In the present embodiment, a plated layer of Sn is formed.

  The steel ball 12 is a sphere made of a conductor, and the size thereof is smaller than that of the electronic component 11 so that the chance of contacting the terminal of the electronic component 11 is increased.

  The bottom plate 2 is divided into eight regions by imaginary lines drawn from its center to eight points that define the outer shape. Specifically, as shown in FIG. 3 and FIG. 4, there are eight regions of region 21a, region 21b, region 21c, region 21d, region 21e, region 21f, region 21g, and region 21h. 2, 3, and 4, the alternate long and short dash line indicates a boundary that is divided into these eight regions. A bottom plate cathode 22a to a bottom plate cathode 22h are formed in the regions 21a to 21h, respectively. These bottom plate cathode 22a to bottom plate cathode 22h are electrically independent from each other.

  Side wall cathode 20a to side wall cathode 20h are formed on side wall 3a to side wall 3h, respectively. Side wall 3a is in contact with region 21a, side wall 3b is in contact with region 21b, side wall 3c is in contact with region 21c, side wall 3d is in contact with region 21d, side wall 3e is in contact with region 21e, side wall 3f is in contact with region 21f, and side wall 3g. Is in contact with the region 21g, and the side wall 3h is in contact with the region 21h. Further, the sidewall cathode 20a is electrically connected to the bottom plate cathode 22a, the sidewall cathode 20b is electrically connected to the bottom plate cathode 22b, the sidewall cathode 20c is electrically connected to the bottom plate cathode 22c, and the sidewall cathode 20d is electrically connected to the bottom plate cathode 22b. 22d, the sidewall cathode 20e is electrically connected to the bottom plate cathode 22e, the sidewall cathode 20f is electrically connected to the bottom plate cathode 22f, and the sidewall cathode 20g is electrically connected to the bottom plate cathode 22g, The side wall cathode 20h is electrically connected to the bottom plate cathode 22h.

  Each of the side wall cathode 20a to the side wall cathode 20h has a shape in which a plurality of conductors extend in the direction parallel to the rotation shaft 7 from the position in contact with the bottom plate 2 on the side wall 3a to the side wall 3h. Yes. In order to increase the area of the entire cathode, it is only necessary to use a planar electrode including these instead of a plurality of conductors. However, if a planar electrode is used, an eddy current may be generated. In this embodiment, a planar electrode is not used. Needless to say, a flat electrode may be used as long as the quality and efficiency of plating is within an allowable range even when eddy current is prevented or eddy current is generated. In the embodiment, there are three conductors, but the number may be increased.

  Connection electrodes 23a to 23h are formed in the regions 21a to 21h outside the container 1 in the bottom plate 2, respectively.

  The connection electrode 23a is electrically connected to the bottom plate cathode 22a, the connection electrode 23b is electrically connected to the bottom plate cathode 22b, the connection electrode 23c is electrically connected to the bottom plate cathode 22c, and the connection electrode 23d is connected to the bottom plate cathode 22d. The connection electrode 23e is electrically connected to the bottom plate cathode 22e, the connection electrode 23f is electrically connected to the bottom plate cathode 22f, the connection electrode 23g is electrically connected to the bottom plate cathode 22g, and the connection electrode 23h is electrically connected to the bottom plate cathode 22h.

  The selection electrode 24 has a cathode-side potential, and when the container 1 rotates counterclockwise in FIG. 4, the connection electrode 23e, the connection electrode 23f, the connection electrode 23g, the connection electrode 23h, the connection electrode 23a, and the connection electrode 23b. The connection electrode 23c and the connection electrode 23d are in contact with each other in this order. Thus, the bottom plate cathode 22e, the bottom plate cathode 22f, the bottom plate cathode 22g, the bottom plate cathode 22h, the bottom plate cathode 22a, the bottom plate cathode 22b, the bottom plate cathode 22c, and the bottom plate cathode 22d are energized in this order. Similarly, the side wall cathode 20e, the side wall cathode 20f, the side wall cathode 20g, the side wall cathode 20h, the side wall cathode 20a, the side wall cathode 20b, the side wall cathode 20c, and the side wall cathode 20d are energized in this order.

  Thus, the reason why the cathode to be energized is switched is to reduce the formation of plating layers on the sidewall cathode 20a to the sidewall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h. This will be described below. The side wall cathode 20a to the side wall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h are exposed, and the electronic component 11 and the steel ball 12 are brought into contact therewith to send negative charges to the terminals of the electronic component 11, thereby causing the terminals of the electronic component 11 to be exposed. It is the role of the plating apparatus to form a plating layer on the substrate, but not all locations of the sidewall cathode 20a to the sidewall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h are in direct contact with the electronic component 11 or the steel ball 12. There are also places where the plating solution 10 is in contact, that is, where it is exposed. In such a place, a plating layer is formed at that portion. Therefore, cutting off the energization to the place where the electronic component 11 and the steel ball 12 do not exist and contact with the plating solution 10 forms the plating layer on the side wall cathode 20a to the side wall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h. It is significant as a method of reducing In other words, the electronic component 11 and the steel ball 12 energize the side wall cathode 20a to the side wall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h that are least exposed. For this reason, the electrode located at the lowermost position in the vertical direction among the connection electrodes 23 a to 23 h is in contact with the selection electrode 24. Connection electrode 23a to connection electrode 23h and selection electrode 24 constitute switching means for switching energization to sidewall cathode 20a to sidewall cathode 20h and bottom plate cathode 22a to bottom plate cathode 22h. Depending on the total volume of the electronic component 11 and the steel ball 12 and the inclination of the rotation axis of the container 1, the plurality of bottom plate cathodes 22a to 22h or the plurality of connection electrodes 23a to 23h may be energized. In such a case, the connection electrode 23a to the connection electrode 23h may be configured to be in contact with two electrodes that are vertically below or in contact with the three electrodes.

  Depending on the rotation speed of the container 1, the position where the exposure is least in the side wall cathode 20 a to the side wall cathode 20 h is not vertically downward but may be a position offset in the rotation direction therefrom. In that case, the position of the selection electrode 24 may be shifted in accordance with that, and the side wall cathode 20a to the side wall cathode 20h that come to the position where the exposure is minimized may be energized.

As an electronic component plating method using the electronic component plating apparatus having the above-described configuration, the container 1
The plating solution 10, the electronic component 11, and the steel ball 12 are put into the container 1, and the positive potential is applied to the anode 4 while the container 1 is rotated by the rotating shaft 7. Plating may be performed by applying a negative potential to the cathode at a certain position. Of course, after the plating layer is formed, the electronic component may be taken out from the container 1.

  In the present embodiment, the plating solution 10 is circulated by the suction nozzle 5 and the supply nozzle 6. The plating solution 10 is an aqueous solution containing metal ions to be a plating layer, but the concentration of metal ions decreases as plating is performed. Therefore, it is necessary to prevent the concentration of metal ions in the plating solution 10 from decreasing. In order to keep the concentration in the barrel containing the electronic component 11 within a certain range as in the prior art, the method in which the barrel side wall is meshed and immersed in the plating tank together with the barrel becomes difficult when the electronic component 11 becomes small. . That is, when the electronic component 11 is plated, it is necessary to make the mesh mesh finer than these in order to prevent the electronic component 11 and the steel ball 12 from passing through the mesh on the side wall of the barrel. However, when the mesh is made finer, the resistance when the plating solution 10 passes through the mesh increases due to the influence of the viscosity and surface tension of the plating solution, and the plating solution 10 in the barrel and the plating solution outside the barrel Insufficient circulation may cause a decrease in the concentration of metal ions in the plating solution. In particular, in the trend of miniaturization of electronic devices, resistors that are one type of electronic components are 0603 (size of 0.6 mm length and 0.3 mm width) and 0402 (length 0.4 mm length and width 0.2 mm). The chip resistor with the outer shape of the size of (3) has been developed, but the appearance of a smaller chip resistor with a size of 03015 (size of 0.3mm in length and 0.15mm in width) or smaller is expected. Under such circumstances, the resistance when the plating solution 10 passes through the mesh becomes larger and circulation through the mesh becomes more difficult. In the present embodiment, since the configuration does not allow the mesh to pass, application to a small electronic component is significant in that respect. Note that a mesh or a filter may be attached to the tip of the suction nozzle 5 to prevent the electronic component 11 and the steel ball 12 from being sucked. Since the suction nozzle 5 sucks in with vacuum or low-pressure air, the passage resistance due to this mesh or filter does not matter.

  Moreover, when the electronic component 11 becomes very small and the area for forming the plating layer becomes very small, there may be a case where the decrease in the concentration of metal ions in the plating solution 10 due to the plating is not a problem. In such a case, it is not necessary to circulate the plating solution 10, and the suction nozzle 5 and the supply nozzle 6 are not necessary.

  In the present embodiment, the side wall cathode 20a to the side wall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h are formed inside the container 1 as cathodes, and the total area of the cathodes is large, so the number of steel balls 12 is reduced. Thus, the plating layer formed on the steel ball 12 can be reduced. Instead, plating layers are formed on the sidewall cathode 20a to the sidewall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h. These cathodes are selectively energized to reduce the formation of the plating layer on the cathode. Therefore, the plating efficiency can be improved comprehensively.

  Further, since the area of the cathode is increased by the side wall cathode 20a to the side wall cathode 20h and the bottom plate cathode 22a to the bottom plate cathode 22h, the number of steel balls 12 interposed in the middle when the electronic component 11 is electrically connected to these cathodes is reduced. Less. The steel ball 12 is a conductor but causes a slight voltage effect. Therefore, a high voltage is applied to the electronic component 11 having a small number of steel balls 12 interposed in the middle, and a low voltage is applied to the electronic component 11 having a large number of steel balls 12 interposed in the middle. The thickness will be different. In the present embodiment, since the area of the cathode is large, the number of steel balls 12 interposed in the middle can be reduced as a whole, variation in the thickness of the plating layer can be reduced, and a more uniform thickness can be applied.

  Note that X in FIG. 1 indicates that the electronic component 11 and the steel ball 12 along the side wall 3 from the bottom plate 2 in the place where the electronic component 11 and the steel ball 12 are present up to the upper side of the container 1 in the side wall 3. It is the length to the upper limit where it is located. On the other hand, Y in FIG. 2 is the height of the side wall cathode 20a to the side wall cathode 20h, that is, the length from the position in contact with the bottom plate 2 to the farthest position in the direction of the rotating shaft 7. In the present embodiment, in order to reduce the formation of a plating layer on the side wall cathode 20a to the side wall cathode 20h in the plating solution 10, X ≧ Y is set to reduce the portion where these electrodes are exposed. .

  In the present embodiment, the voltage application of not only the side wall cathode 20a to the side wall cathode 20h but also the bottom plate cathode 22a to the bottom plate cathode 22h is switched, but depending on the shape of the container 1 and the inclination angle of the rotating shaft 7, the bottom plate 2 The inner surface of the container 1 may always be in a state where the electronic component 11 and the steel ball 12 are present. In such a case, the bottom plate cathode 22a to the bottom plate cathode 22h are not electrically connected to the side wall cathode 20a to the side wall cathode 20h, and are always applied to the bottom plate cathode 22a to the bottom plate cathode 22h during plating. Also good. Alternatively, the bottom plate cathode 22a to the bottom plate cathode 22h may be used as one electrode and applied constantly during plating.

  In the present embodiment, the container 1 is a regular octagon and the bottom plate 2 is a regular octagon. However, the present invention is not limited to this, and a regular n prism and a regular n prism (where n ≧ 3) can be used. When n becomes small, the smooth movement of the electronic component 11 and the steel ball 12 accompanying the rotation of the container 1 is impaired, and the electronic component 11 may be impacted. On the other hand, when n increases, the movement of the electronic component 11 and the steel ball 12 becomes smooth. However, since the number of the side walls 3 and the cathodes formed on the side walls 3 increases, the switching of conduction by the switching means increases and the apparatus becomes complicated. Become. From the above points, n is preferably about 6 to 8.

  Examples of the electronic component that forms a plating layer with the plating apparatus in this embodiment include a chip resistor and a chip inductor, but application to other electronic components is also possible.

  The barrel plating apparatus and the electronic component manufacturing method using the barrel plating apparatus according to the present invention are useful for plating electronic parts used in electronic devices and the like.

DESCRIPTION OF SYMBOLS 1 Container 2 Bottom plate 3 Side wall 3a Side wall 3b Side wall 3c Side wall 3d Side wall 3e Side wall 3f Side wall 3g Side wall 3h Side wall 4 Anode 5 Suction nozzle 6 Supply nozzle 7 Rotating shaft 8 Shaft 9 Base 10 Plating liquid 11 Electronic component 12 Steel ball 20 20b side wall cathode 20c side wall cathode 20d side wall cathode 20e side wall cathode 20f side wall cathode 20g side wall cathode 20h side wall cathode 21a region 21b region 21c region 21d region 21e region 21f region 21g region 21h region 22a bottom plate cathode 22c bottom plate cathode 22b bottom plate cathode 22b Bottom plate cathode 22f Bottom plate cathode 22g Bottom plate cathode 22h Bottom plate cathode 23a Connection electrode 23b Connection electrode 23c Connection electrode 23d Connection electrode 23e Connection electrode 23f Connection electrode 23g Connection electrode 23h Connection electrode 2 Selective electrode

Claims (4)

A regular n-gonal bottom plate;
N sidewalls in contact with each of the n sides of the regular n-gon that form the outer shape of the bottom plate;
A container which is an outer shape of a regular n prism formed by the bottom plate and the side wall and does not allow liquid to pass through the bottom plate and the side wall;
Rotating means for rotating the container on a rotation axis that is perpendicular to the bottom plate through the center of the bottom plate and tilted less than 90 degrees from the vertical direction;
N sidewall cathodes electrically independent of each other inside the container of the n sidewalls,
Switching means for switching conduction to the n side wall cathodes;
An anode entering the space inside the container;
Barrel plating equipment with The inner surface of the container of the bottom plate has n regions divided by imaginary lines drawn from the center of the bottom plate to each point of the outer shape of the bottom plate,
N bottom plate cathodes electrically independent from each other in each of the n regions of the bottom plate,
The bottom plate cathode is electrically connected to the side wall cathode provided on the side wall in contact with the side of the region of the bottom plate where the bottom plate cathode is located;
The barrel plating apparatus according to claim 1. In the barrel plating apparatus according to claim 1, a step of introducing an electronic component into the container containing a plating solution;
The step of rotating the container by the rotating means, applying a positive potential to the anode, and applying a negative potential to the side wall cathode that is least exposed among the n side wall cathodes by the switching means. When,
Stopping the container by the rotating means and taking out the electronic component from the container;
A method of manufacturing an electronic component comprising: A step of charging a plating solution and an electronic component into the container in the barrel plating apparatus according to claim 2,
The container is rotated by the rotating means, a positive potential is applied to the anode, and the switching means electrically connects the side wall cathode with the least exposure among the n side wall cathodes and the side wall cathode. Applying a negative potential to the bottom plate cathode, and
And a step of stopping the container by the rotating means and taking out the electronic component from the container.

Images